Sustainable Building Technical Manual - Etn-presco.net

can be extreme. However, in a hot, humid climate like that of the Southeast UnitedStates, lightweight construction and high ceilings may be beneficial.– Life-cycle cost and maintenance requirements. Over the useful life of a commercialbuilding, which may be 30 or more years, some materials will require maintenanceand replacement more than once. When the full range of costs is considered, materialsthat are more costly upon initial purchase may be justified in terms of “avoidedfuture costs.” The higher initial cost may also be justified if the product comparesfavorably with others over their life cycle. (See Chapter 2, “Selecting Environmentallyand Economically Balanced Building Materials,” for a discussion on life-cycle cost.)– Resource recovery and recycling. Once a material has completed its initial service in abuilding, it potentially has additional use as a resource and can later be recoveredand recycled. The potential recyclability of metal, plastic, glass, wood, and masonryare discussed below.a. Metals are recyclable if they can be separated by type. Accordingly, steel andaluminum building elements have a high recycling value. Approximately 50 to70 percent of the energy and pollution from steel production can be avoided bycurrent recycling technology. 1 Up to 85 percent of the energy and pollutionfrom aluminum manufacturing can be avoided by remelting.b. Most plastics are recyclable, but the current rates of recycling are not highbecause the wide variety of plastics in use makes them difficult to separate.Some plastics such as pure polyvinyl chloride (PVC) would be recycled frombuildings more often if designed for easy removal. Additives, coatings, and colorantsmake recycling difficult.c. Glass products are recyclable if separated and uncontaminated; however, littlerecycling of glass building products now occurs. Recycled glass products aremade with consumer container glass salvaged from the waste stream. Remeltingglass offers only a marginal energy and pollution reduction. 2d . Heavy timber is recyclable by salvaging and by resawing. Engineered structuralwood products, wood panels, and millwork are candidates for salvage and reuse,particularly if they are fastened in such a way that they can be easily removed.e . Concrete, clay, and other masonry products and ceramics are examples of materialsthat are usually difficult to salvage and reuse. Some recycling of these productsoccurs by crushing them for use as granular fill in road and sidewalk base.Health and Indoor Air Quality Issues★ S I G N I F I CA N C E .Poor indoor air quality is caused by outdoor and indoor sources of gaseous and particulateair pollutants that exceed the capacity of the building’s ventilation and filtrationequipment to dilute or remove them to an acceptable level. 3 Although many pollutantsoriginate outdoors or from occupant activities, equipment, and processes, other pollutantsare generated from materials. 4 The various types of indoor air pollutants are:■ Volatile organic compounds (VOCs) emitted by interior materials and their components;■ VOCs emitted by cleaning and maintenance products periodically used with thosematerials (see Chapter 22, “Housekeeping and Custodial Practices”);■ Fiber shed from textiles, insulation, and panel products;■ Soil, biological materials (e.g., fungi and bacteria), and gases released by biologicalactivity; and■ Dust and other particulates from spraying, sanding, or finishing.These material-based pollutants may affect the health and productivity of buildingoccupants, maintainence personnel, and construction tradespeople. (See Chapter 13,“Indoor Air Quality” for further discussion on this topic.)